Patent Document 1 discloses a typical prior art related to such a safety device for medical needles.
The applicant discloses in Patent Document 2 a structure that solves the problem of Patent Document 1.
Hereinafter, reference signs of the members of Patent Document 2 are bracketed by < > in the description of Patent Document 2, FIGS. 5(A), 5(B), 6(A) and 6(B) in order to avoid confusion with the reference signs of the present invention.
A second invention described in Patent Document 2 (hereinafter, the invention of Patent Document 2) has a structure in which the first and second leg portions <31, 32> are extended, the distal end <23> of the needle <21> is introduced into the space <40S> of the shield member connection hub <40H′> and further, the lower wall <42B′> of the connection hub <40H′> shifts its position so as to block the cross section of the opening portion <40O′> of the connection hub <40H′>.
FIGS. 35(A) and 35(B) of Patent Document 2 discloses a condition (the second state) where the cross section of the opening portion <40O′> of the connection hub <40H′> (or the neighborhood of the opening portion <40O′>) is blocked by the lower wall <42B′> of the slide member <42′> and the distal end <23> of the needle <21> is accommodated in the space <40S> to be protected (shielded).
Document 1 JP2007-511285A (claims, FIGS. 1-7 and FIGS. 16-28; patent family U.S. Pat. No. 7,351,230)
Document 2 US2013/0172826A1, FIGS. 24-53 and paragraphs [0314]-[0438]
However, since the invention of Patent Document 2 (medical needle safety apparatus 101) has a structure in which the shield member connection hub <40H′> is inserted in the fixing member connection hub <50H′> (see FIGS. 29(A) and 29(B) of Patent Document 2 corresponding to FIGS. 5A and 5B of the present application], when transition is made from the first state to the second state (FIGS. 35(A) and 35(B) of Patent Document 2), the following problem is pointed out:
In practice, as shown in FIGS. 6A and 6B, there are cases where the upper side of the distal end DE side of the lower wall <42B′> of the slide member <42′> is caught on the proximal end PE side at a lower side of the shield member first latching portion <48> and the cross section of the space <40S> of the shield member connection hub <40H′>, the opening portion <40O′> (or the neighborhood of the opening portion <40O′>) cannot be blocked.
In the above cases, the contact portion S of the upper side of the distal end DE side of the lower wall <421T> and the lower side of the proximal end PE side of the shield member first latching portion <48> is weak in the penetration resistance of the distal end <23> of the needle <21> because the wall is thin.